It was dark and getting colder when van Gorp started the last three circuits of the 10-lap course through the Naseby Forest.
She completed the race in 14hr 17min.
She picked her way along the track by using a head lamp that lit up the track 1m in front of her.
"It became hypnotic watching the small dot on the black canvas," she said.
Van Gorp (nee Murray) was supported by her husband Wayne and two other runners who stayed with her during the last 30km.
She had started running at 7am on Saturday and the other 29 runners completed the event in daylight.
Van Gorp did not complete the journey until 9.17pm.
"I was bone tired. I was shattered," van Gorp said yesterday.
"It was the hardest physical thing I have ever done."
Van Gorp (40), a personal trainer and massage therapist, completed the first 50km in 6hr 21min.
The second 50km took 7hr 56min.
The last 30km in the dark took 4hr 45min.
What was the hardest part of the race?"It was getting freezing cold and the ground was icing up when it got dark and I was scared they were going to stop me," van Gorp said.
"I wanted to complete the 100km. At no time was I going to stop."
She has raced three marathons, but only started ultra-distance racing in the Kepler challenge two years ago.
"I just wanted something to challenge myself," she said.
"I'm a personal trainer and tell my clients to set goals for themselves.
"I get satisfaction from setting personal goals and achieving them.
"They were thinking of pulling me out at 90km but that would have shattered me and been too hard to handle."
What was it like when she reached the finish?
"I was elated," van Gorp said.
"I was rapt. It was amazing standing there in the pitch black night in the middle of the Naseby Forest. It was really satisfying."
Van Gorp kept running for the first 60km but mixed in some walking during the last 30km.
"In the last three laps every little mound felt like a huge mountain," she said.
It usually takes a month to recover from a hard run marathon.
A 100km run recovery is expected to take longer.
"I'd like to know how long it will take," van Gorp said.
"I've no idea. But I've got no desire to put on running shoes at the moment."
Van Gorp received expert advice from her colleagues at the World Fitness Gymnasium about what to eat during the race.
Her diet during the 14 hours consisted of bananas, jelly beans, muesli bars, scroggin, ice buns, and chocolate which she took at the end of each lap.
She carried a bottle of mineral and vitamin rich Replace drink and drank water at each 5km drink station to keep hydrated.
The hardest part of her training was the two 6hr runs she ran in July.
One over the hills to Waikouaiti and the other one over the Swampy Summit and Mount Cargill circuit.
Van Gorp grew up in Dunedin and was a keen football player at Macandrew Intermediate and Queens High School.
She met her husband when he was her coach at the Roslyn Wakari club.
He is the son of Otago football guru Barry van Gorp.
She started running around the block to get fit in 1999 and joined the Hill City Athletics Club the following year.
